Method and apparatus for forming headed articles



0. H. DE LAPOTTERIE. 7 METHOD AND APPARATUS FOR FORMING HYEADED ARTICLES.

APPLICATION FILED MAR. I, 1918- RENEWED APR. 8.1921. 1,417,806.

Patented May 30, 1922'.

UNITED STATES PATENT OFFICE.

OTTO H. DE LAPOTTERIE, OF OHIO, ASSIGNOR TO TOWNSEND COMPANY, OF

NEW BRIGHTON, PENNSYLVANIA, A CORPORATION OF -PENNSYLVANIA.

, METHOD m1) APPARATUS FOR FORMING BEADED ARTICLES.

To all whom it may concern:

Be it known that I, O'r'ro .H. on LAPOTTERIE, a citizen of the United States, residi at Kent, in the county of Portage and S tate of Ohio, have invented certain new and useful Improvements in Methods and Apparatus for Forming Headed Articles, of which the following is a specification.

My invention relates to a method and aplike, and has for its principal object to produce an improved -rivet in'which that .por-

.tion only of the blank which forms the rivet head has been heated to a temperature high enough to facilitate upsetting of the head.

My improvements may be applied, for example, to heading machines of the kind now commonly used for hot or cold rivet making. Such machines usually comprise means for feeding a long length of metal stock, a rod or bar into the machine, means for shearing off a blank and means for heading the blank to form thedesired article; and are usually automatic or semi-automatic in o eration.

y invention comprises the addition to such machines 0 means for heating the metal which is to form the rivet or like article while it is in the machine and prefer ably during the process of shearing the rivet blank from the stock-bar or rod.

The heating is preferably performed by subjecting the rod or bar or only a portion thereof to electrically produced heat, the rod, bar or other metal stock itself forming part of an electric circuit. The electrical apparatus may be of any Well known type capable of furnishing. a current-of high amperage at low voltage.

A specific example of my invention is hereinafter described" as it has been applied Specification of Letters Patent. Patented May 30 1922. Application filed Karen 1, 1918, Serial n. 219,841.

Renewed April 8, 1921. Serial No. 459,716.

to a machine. for rivets.

That portion of in which my shown in the which a Figure 1 is a vertical sectional elevation;

ig. 2 is an end view of Fig. 1;

Fig. 3 is a plan of Fig. 1;

F ig. 4 shows the position of the parts with the gripping dies open;

F1g. 5 shows the position of the dies when the blank has been partially sheared off;

Fig.- 6 shows the gripping position of the dies with the sheared ofi? blank ready to be headed;

Fig. 7 shows a usual type of cold-formed rivet;

Fig. 8 shows a rivet formed by the present invention;

making headed nails or Fig. 9 shows a rivet of the shape produced by hot-forming. I

In Fig. 1, A is the bed plate of the machine in which are mounted the usual fixed die block D carrying one gripping die N and the movable or reciprocatmg die block S carrying the other gripping die E. The means for moving or reciprocating the die block S are not shown as they are well known in the art and form no part of my invention.

K is the-stockbar or rod from which the rivet blanks are cut oil and is preferably of cold-drawn steel. This rod is fed forward either by hand or preferably by automatically actuated rolls B -B, the lower roll being mounted on and actuated through shaft C the shaft of the upper roll being mounted in the housing I.

F is a back plate carrying the cutting ofi' die 0 which is insulated from the back plate and bed plate by insulation 0. J is a feed tube surrounded by an insulating tube J mounted in an opening in the bed plate, its innerend registering with the central opening in the die 0'. H is the heading tool mounted on a header-slide G and actuated in the usual manner.

Current is delivered to the machine from any suitable source, such as a dynamo 1 and transformer 2, one side of the circuit being connected to conductor R, shown as clamped to the bed plate by an insulated bolt M. This conductor R is connected to a brush or brushes Q bearing against the lower feedroll B, this roll being insulated from the shaft C but mechanically connected thereto by an insulated key L. Any other means for insulating the rolls may be used.

The other side of the circuit is connected by conductor R and bolt M to the stationary die block D, both die blocks and dies and the bed plate being thus electrically connected.

In practice a low voltage is used, but the circuit is so designed as to carry a current of large amperage.

It will thus be apparent that the stock-bar or rod K when fed through the feed pipe J and die 0 is electrically insulated from the rest of the machine until it is brought into contact with the movable die.

W is a friction disk or brake arranged to prevent any backward movement of the feed roll so that the end of the stock-bar or rod in the machine is held in contact with the surface of the moving die block for a purpose herinafter stated.

The operation of the machine is as follows The bar or rod to be headed is fed by the feed rolls through the tube J and die 0 until a length sufficient to form a rivet or the like extends beyond the die. The extent to which the rod projects may be controlled in the usual way by a stoclvgauge.

The movable die E then travels across the face of die 0 and shears off the blank. As soon as die E comes into contact with the rod K, electrical connection is made and current flows through the rod and tends to heat the same. As the cross section of the bar is gradually diminished by the action of the die, the electrical resistance of the bar at this portion increases with a consequently large localized development of heat, which in practice has been found to be sufficient to cause that portion of the end of the rod within the die 0 to be raised to the desired temperature. As the protruding portion of the rod is in contact with the massive die, its temperature is not raised to any material extent, but that portion of the rod K within the die 0 is rapidly raised to the temperature desired, and by proper adjustment of the conditions as to time of operation and quantity of current, this heated portion may be made to extend only through that part of the rod which is later to be made into the head of the rivet.

The movable die, in its further movement, completely shears off the blank and griis it against the stationary die, whereupon the heading tool advances and heads the rivet. The movable die then moves back to its original position and the operation is repeated. During the back and forth movement of the movable die, it moves across the end of the sheared rod with which it makes a more or less imperfect electrical contact, the passage of the current through this relatively high resistance connection causing a further 10- calized heating of the end portion of the rod which continues as long as the movable die is in contact with the rod.

At each succeeding operation, therefore, a blank with a heated head portion is brought into position opposite the heading tool which forms the head into any of the desired shapes which can be made by hot riveting, while the shank remains substantially cold.

The finished rivets are ejected from the dies by an automatic kick-out or in any of the other well known ways.

The improved rivet made by my machine has an accurately gauged shank with a squarely cut off end, and can have any desired form of head, for example, that shown in Fig. 8, which could not be made cold, the shape shown in Fig. 7 being the best that can be done by the cold rivet making process.

A hot-formed rivet can be made with a pointed head, as shown in Fig. 9, but its shank is liable to be distorted from a true cylindrical shape, and the shearing is liable to produce an irregular and inclined end instead of one at right angles to the axis of the shank. The irregularities in the ends of hot formed rivets cause diiliculty when the rivets are set in plates having chamfered openings, since the openings are not uniformly filled flush with the surface of the plate and the superfluous metal must be chipped off. My new form of rivet obviates this difficulty.

In actual operation, I have found that the end portion of the blank can be electrically heated by the means described to such a temperature that it will readily flow under the action of the heading tool. The heating of the end portion of the rod, which is later to form the head portion oi the rivet, moreover. can be so localized that the adjacent portion of the rod which later forms the shank of the rivet remains practically unheated, this condition being maintained during the shearing operation because of the close physical contact of this shank portion of the blank with the massive die, the previously heated end portion of the blank extending beyond said die.

My invention is applicable not only to rivets. but to nails. bolts or other headed articles of iron, steel. copper, bronze or other metals; and while I have shown my invention as applied to one form of heading machine it is obviously applicable to other forms of machines and is further not to be limited to the particular details of construction shown.

Obviously also the machine may be used to heat more than the head-"forming portion of the stock-bar or rod. so that the arti-. cles are formed by the usual hot-forming process. This result can be obtained bv proper variation of the factors of time and quantity of current. It the machine is 1,417,soe

subjected to the heating action of the current for a longer time, or if a larger current is used,'any desired extent of the bar or rod may be heated to any predetermined temperature.

The invention is also obviously applicable to the format-ion of articles from any kind of metal stock, whether continuous or not, as long as it is in such shape, form or condition as will permit of its being fedinto, and

electrically heated to a working temperature,

in machines by which it is into formed articles.

I believe that I am the first to make, by machinery, an article formed as an entirety from stock electrically heated within a machine to a temperature at which the solid manufactured metal will flow and in which machine the heated metal is shaped by pressure to form the article.

I claim: 1. In a headin of means for fee ing a rod or bar, means for shearing a blank therefrom comprising a movable die, and means for passing an elec- (tiric current through said rod or bar and said 1e.

2. In a heading machine, the combination of a bed plate, a cut off die insulated therefrom, insulated means for feeding a rod or bar to said die, a movable die, and means for delivering electric energy to said feeding means and movable die, whereby the rod is included in an electric circuit.

3. In a heading machine, the combination with means for feeding a rod or bar, of

. die to shear off a blank, means for feeding means for shearing off a portion of said rod, and means for electrically heating said rod during the shearing operation. p

4. In a heading machine, the combination with a cutting-off die, a movable die ar ranged to cooperate with said cutting-off machine, the combination ing the cross section of the a rod or bar through said cutting-off die,

and means for electrically heating the end portion of said rod with nsaid cutting-off die, said movable die being arranged to engage the unheated portion of said blank.

I 5. In a heading machine, the combination of heading mechanism, a stationary clamping die, "a' movable clamping die, means for electrically heating the end p0r-.

tion of a blank, and means for feeding said heated blank to said clamping dies.

6. In a heading machine, the combination of heading mechanism, a stationary clamping die, a movable clamping die, means for electrically heating a blank, and means for feeding said heated blank to said clamping dies.

.7. In a heading machine, the combination of a cutting-off die, means for feeding a rod or bar therethrough, means for electrically heating a portion of said rod or bar, a mov- -able die arranged to shear off a blank from said rod, a stationary die arranged to cooperate with said movable die to hold the blank, and a heading device.

8. Themethod of making headed metal articles, which consists in electrically heating a portion only of the metal from which the article'is to be formed by causing sufiicient current to pass through said metal and gradually diminishing the cross section of the metal during the passage of the current,

and thereafter forming the article from said heated portion. g

9. The methodof makin headed metal articles, which consists in e ectrically heating the metal from which the article is to be formed by causing sufiicient current to pass through said metaland gradually diminishmetal durin the passage of the current, and thereafter orming the article from said heated portion. In testimony whereof, I afiix my signature.

OTTO H. DE LAPOTTERIE. 

